Reforestation project system and reforestation project program

ABSTRACT

A reforestation project system is provided which is capable of devising and evaluating a reforestation project, the reforestation project comprises a project database for storing reforestation projects; a tree-type database, a condition information-collecting means for collecting the tree diameters and tree heights within local areas in a plurality of proposed reforestation sites input from the terminals; a reforestation site determining means for determining a reforestation site by calculating carbon dioxide absorption amounts at the present point in proposed reforestation sites from the tree diameters and tree heights in the local areas, and selecting a reforestation site having a determined carbon dioxide absorption amount that is smaller than a first threshold; a project devising means for calculating an maximum economic profit and maximum absorption of carbon dioxide when planting area in the reforestation site and the tree-types stored in the tree-type database are respectively changed.

CROSS-REFERENCE

The present application is based on a Japanese Patent Application No.2002-333526 filed Nov. 18, 2002, and the content of the Japaneseapplication is incorporated herein by reference.

TECHNICAL FIELD

This invention relates to a reforestation project system and areforestation project program, capable of devising and evaluating thereforestation project.

BACKGROUND ART

Conventionally, it has been known to device a reforestation(hereinafter, the term “reforestation” means both reforestation andafforestation) project by making a reforestation simulation using asingle tree type. Since reforestation process takes many tens of yearsfrom planting to cutting, a simulation is a useful means for optimizinga reforestation project program. Furthermore, in natural forests orartificial plantations of needle-leaf trees, a quantitative thinningmethod is known, which makes it possible to estimate the state of theplantations and an accumulated amount of trees, by managing the forestso as to satisfy a predetermined relationship between the number ofremaining trees per unit area and the age of the trees. (JapaneseUnexamined Patent Application, First Publication No. 5-111335).

On the other hand, reforestation is recently attracting attention as aCDM. CDM is an abbreviation of “Clean Development Mechanism”. CDM is amechanism, in which a developed country, which has a target amount forreducing the discharge amount of greenhouse effect gas, acquires theamount of discharged gas reduced in developing countries and uses theresultant amount of reduced discharge as a discharge frame in its owncountry. The reforestation is one candidate among a plurality of CDMprojects (e.g. “Clean Development Mechanism Countdown: NewCountermeasures for Warming, Widening Business Opportunities” NikkeiEcology October 2002, Nikkei Shinbunsha, 8 Sep. 2002, Vol. 40, pp.98-101).

Since the aim of reforestation is to sell trees that have been cut at ahigh price, the aim may be attained when trees that are easy to grow andtrees that can be sold at a high price are planted over a wide area.However, since the market price of wood fluctuates depending on balancebetween supply and demand, the market price for a certain tree is notnecessary high at the time of harvest of the wood. However, if theharvest time is delayed until the wood prices becomes high, there is arisk of degrading the wood which may results in degradation of themarket price. In general, trees that are traded at high processgenerally have risks such as not growing sufficiently due to insectdamages or the like. Moreover, it is necessary to devise a reforestationproject so as to plant appropriate trees which match to the particularenvironment, and in addition, it is necessary to devise a project takingadverse effects into consideration which may cause bad influences on thesurrounding environment by reforestation.

While reforestation is attracting attention as an effective measureagainst global warming, in order to implement reforestation forpreventing global warming, it is necessary to devise a detailedreforestation project program so as to maximize the amount of carbonthat accumulates in the trees as they grow. In order to attain theabove-described objects, it is important to precisely identify theconditions of proposed reforestation site, and the amount of carbonaccumulated in the proposed reforestation site, and, based on the amountof accumulated carbon, the proposed reforestation site must be evaluatedand determined whether the proposed site or site is the proper site forreforestation. Conventionally, it was difficult to determine thereforestation site by the conventional method and, the conventionalmethod is not appropriate for constructing a reforestation program thatcan maximize the carbon accumulation for preventing global warming.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a reforestationproject system and a reforestation project program that can devise andevaluate a reforestation project in accordance with the aim of thereforestation.

A reforestation project system of the present invention comprising, acomputer server capable of communicating through internet with terminalsinstalled in sites where reforestation is carried out, for devising andevaluating a reforestation project, a project database for storingreforestation projects, a tree-type database, in which tree-type datafor each tree-type are stored, a condition information-collecting meansfor collecting tree diameters at a breast-height and tree heights withinlocal regions in a plurality of reforestation boundary sites input fromsaid terminals, a reforestation site determining means for determining areforestation site by calculating carbon dioxide absorption amounts by apredetermined equations at each reforestation candidate sites from thetree diameters at the breast-height and tree heights in said localregions, and selecting a reforestation candidate site having adetermined carbon dioxide absorption amount that is smaller than a firstthreshold, a project planning means for calculating a profit whenplanting area in said reforestation site and the tree-types stored insaid tree-type database are respectively changed, selecting a tree-typeand the planting area that can obtain the greatest profit, and storingthe selected tree-type, planting area, and estimated values for growthchange of the trees, as reforestation project information in saidproject database; and a project output means for displaying saidreforestation project information, stored in said project database, atsaid terminals.

A reforestation project system of the present invention comprising, acomputer server capable of communicating through the internet withterminals installed in sites where reforestation is carried out, anddevising and evaluating a reforestation project; a project database forstoring obtained reforestation projects, a tree-type database, in whichtree-type data for each tree-type are stored, a conditioninformation-collecting means for collecting the tree diameters at thebreast height and tree heights of all trees within each local region ina plurality of reforestation candidate sites input from said terminals,a reforestation site determining means for performing a predeterminedcalculation to determine the average carbon dioxide absorption amountper unit volume at the present point in the reforestation candidatesite, from the tree diameters at the breast height and tree heights thatwere received, selecting a reforestation candidate site having adetermined average carbon dioxide absorption amount that is smaller thana first threshold, deeming this reforestation candidate site to be thereforestation site, and outputting the tree diameters at the breastheight and tree heights of the trees in the reforestation candidatesite, and information for identifying the reforestation candidate site,a first calculating process that inputs said tree diameters at thebreast height and tree heights, and calculates the average diameter andaverage tree height at each tree age, a second calculating process thatdetermines tree number distribution and tree height distribution foreach tree diameter by calculation, a third calculating process thatdetermines log volume of each diameter per unit area, based on said treenumber distribution and tree height distribution for each tree diameter,by calculation, a fourth calculating process that multiplies thereforestation site area by said log volume, thereby determining the logvolume of the entire reforestation site, and multiplies this log volumeof the entire reforestation site by a log price for each diameter,thereby determining an economic value for the entire reforestation site,a project devising means for repeatedly executing the first, second,third, and fourth calculating process for each tree-type stored in saidtree-type database so as to determine the economic value of the entirereforestation site in the case where the reforestation site volume hasbeen changed, selecting a tree-type and reforestation site volume thatobtain the highest economic value determined by said fourth calculatingprocess, and storing the selected tree-type, planting area, andestimated values for growth change of the trees, as reforestationproject information in said project database and a project output meansfor displaying said reforestation project information, stored in saidproject database, at said terminals.

The reforestation project system according to the above aspect, furthercomprising an indirect effect memory means, in which is storedbeforehand information relating to indirect effects of each environmentof the reforestation site and the scale of the reforestation, obtainedby prior investigation, a risk memory means, in which is storedbeforehand risk information of each environment of the reforestationsite and the scale of the reforestation, obtained by priorinvestigation, an indirect effect estimating means, which reads aproject value of indirect effects corresponding to the scale of thereforestation project and the reforestation site, read from said projectdatabase, from said indirect effect memory means, and stores it in saidproject database; and a risk estimating means, which reads a projectvalue of risks corresponding to the scale of the reforestation projectand the reforestation site, read from said project database, from saidrisk memory means, and stores it in said project database.

The reforestation project system according to the third aspect, furthercomprising an indirect effect collecting means, which receives andcollects condition information relating to indirect effect estimates,input from said terminal, a risk collecting means, which receives andcollects condition information relating to risk estimates, input fromsaid terminal, a project accomplishment status determining means, whichreceives condition information, indirect effect information, and riskinformation, respectively from the condition information-collectingmeans, the indirect effect information collecting means, and the riskinformation collecting means, compares them with estimate values andproject values that are stored in said project database, and calculatesa proportion of conditions with respect to said project; and a projectreview means, which, when said reforestation project is deemedincomplete from the proportion of conditions with respect to saidproject, re-devises said reforestation project, and stores it in saidproject database, said indirect effect estimating means and riskestimating means re-estimating indirect effect and risk based on thereviewed project that was stored in said project database.

The reforestation project system according to the first aspect, whereina second threshold smaller than said first threshold is set, and, in thecase where the amount of carbon dioxide obtained is smaller than saidfirst threshold and greater than said second threshold, the presentsecondary forest is cut and deemed a reforestation site for newreforestation.

A reforestation project program, operated on a reforestation projectsystem that comprises a computer server capable of communicating throughthe internet with terminals installed in sites where reforestation iscarried out, and devising and evaluating a reforestation project, thecomputer server being comprised of a project database for storingreforestation projects and a tree-type database, which tree-type datafor each tree-type are stored in, the reforestation project systemallowing a computer to execute a condition information-collectingprocess for collecting tree diameters at the breast height and treeheights within local regions in a plurality of reforestation candidatesites input from said terminals, a reforestation site determiningprocess of determining a reforestation site by performing apredetermined calculation to determine carbon dioxide absorption amountsat the present point in the reforestation candidate sites from the treediameters at the breast height and tree heights of trees in said localregions, and selecting a reforestation candidate site having adetermined carbon dioxide absorption amount that is smaller than a firstthreshold, a project devising process of performing a predeterminedcalculation to determine profit when planting area in said reforestationsite and the tree-types stored in said tree-type database arerespectively changed, selecting a tree-type and planting area that canobtain the greatest profit, and storing the selected tree-type, plantingarea, and estimated values for growth change of the trees, asreforestation project information in said project database; and aproject output process of displaying said reforestation projectinformation, stored in said project database, at said terminals.

A forestation project program, operated by a reforestation projectsystem that comprises a computer server capable of communicating throughthe internet with terminals installed in sites where reforestation iscarried out, and devising and evaluating a reforestation project, thecomputer server being comprised of a project database for storingreforestation projects and a tree-type database, which tree-type datafor each tree-type are stored in, the reforestation project systemallowing a computer to execute a condition information-collectingprocess of collecting the tree diameters at the breast height and treeheights of all trees within each local region in a plurality ofreforestation candidate sites input from said terminals, a reforestationsite determining process of performing a predetermined calculation todetermine the average carbon dioxide absorption amount per unit volumeat the present point in the reforestation candidate site, from the treediameters at the breast height and tree heights of all trees that werereceived, selecting a reforestation candidate site having a determinedaverage carbon dioxide absorption amount that is smaller than a firstthreshold, deeming this reforestation candidate site to be thereforestation site, and outputting the tree diameters at the breastheight and heights of all trees in the reforestation candidate site, andinformation for identifying the reforestation candidate site, a firstcalculating process of inputting said tree diameters at the breastheight and tree heights, and calculating the average diameter andaverage tree height at each tree age, a second calculating process ofdetermining tree number distribution and tree height distribution byinputting tree diameters at the breast height and tree heights bycalculation, a third calculating process of determining a log volume ofeach diameter per unit area, based on said tree number distribution andtree height distribution for each tree diameter by calculation, a fourthcalculating process of multiplying the reforestation site area by saidlog volume, thereby determining the log volume of the entirereforestation site, and multiplying this log volume of the entirereforestation site by a log price for each diameter, thereby determininga economic value for the entire reforestation site, a project devisingprocess of repeatedly executing the first, second, third, and fourthcalculating process for each tree-type stored in said tree-type databaseso as to determine the economic value of the entire reforestation sitein the case where the reforestation site volume has been changed,selecting a tree-type and reforestation site volume that obtain thehighest economic value determined by said fourth calculating process,and storing the selected tree-type, planting area, and estimated valuesfor growth change of the trees, as reforestation project information insaid project database; and a project output process of displaying saidreforestation project information, stored in said project database, atsaid terminals.

The reforestation project program according to the present invention,further allowing a computer to execute an indirect effect memory processof storing beforehand information relating to indirect effects of eachenvironment of the reforestation site and the scale of thereforestation, obtained by prior investigation, a risk memory process ofstoring beforehand risk information of each environment of thereforestation site and the scale of the reforestation, obtained by priorinvestigation, an indirect effect estimating process of reading aproject value of indirect effects corresponding to the scale of thereforestation project and the reforestation site, read from said projectdatabase, from said indirect effect memory means, and storing it in saidproject database; and a risk estimating process of reading a projectvalue of risks corresponding to the scale of the reforestation projectand the reforestation site, read from said project database, from saidrisk memory means, and storing it in said project database.

The reforestation project program according to the above aspect, furtherallowing a computer to execute an indirect effect collecting process ofreceiving and collecting condition information relating to indirecteffect estimates, input from said terminal, a risk collecting process ofreceiving and collecting condition information relating to riskestimates, input from said terminal, a project accomplishment statusdetermining process of receiving condition information, indirect effectinformation, and risk information, respectively in the conditioninformation-collecting process, the indirect effect informationcollecting process, and the risk information collecting process,comparing them with estimate values and project values that are storedin said project database, and calculating a proportion of conditionswith respect to said project; and a project review process ofre-devising said reforestation project and storing it in said projectdatabase when said reforestation project is deemed incomplete from theproportion of conditions with respect to said project, said indirecteffect estimating process and risk estimating process re-estimatingindirect effect and risk based on the reviewed project that was storedin said project database.

The reforestation project program according to the above project,wherein a second threshold smaller than said first threshold is set,and, in the case where the amount of carbon dioxide obtained is smallerthan said first threshold and greater than said second threshold, thepresent secondary forest is cut and deemed a reforestation site for newreforestation.

According to the above-described constitution, the reforestation projectis planned based on the present condition of the reforestation site,while estimating indirect effects and risks, thereby enabling thereforestation project to be devised easily. Further, while executing theproject, the accomplishment status of the project is assessed based oncondition information, indirect effect information, and riskinformation, and the project is reviewed based on these assessments,enabling the reforestation project to be reliably executed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing a reforestation project systemaccording to an embodiment of this invention.

FIG. 2 is a flowchart showing an operation for devising and evaluating areforestation project.

FIG. 3 is an explanatory diagram showing a local region in areforestation sites.

BEST MODE FOR CARRYING OUT THE INVENTION

A preferred embodiment of the reforestation project system according tothe present invention will be explained with reference to the attachedfigures.

FIG. 1 is a block diagram showing a constitution of the embodiment. InFIG. 1, reference numeral 1 represents a reforestation project systemfor devising and evaluating a reforestation project, which comprises acomputer server. Reference numerals 3 represent reforestation siteterminals, which can communicate with the reforestation project system,installed in local offices at reforestation sites, including thoseoversea sites, and these terminals are owned by individuals or businessenterprise conducting forestry work in the those sites. In the casewhere large-scale reforestation is to be implemented, a reforestationsite terminal 3 is installed for each reforestation site. By way ofexample, FIG. 1 shows three reforestation site terminals. Referencenumeral 4 represents internet, which is used for exchanging informationbetween the reforestation site terminals 3 and the reforestation projectsystem 1.

Reference numeral 11 represents a present conditioninformation-collecting section for collecting information relating topresent condition of each reforestation site, input from thereforestation site terminals 3. Reference numeral 12 represents anamount of accumulated carbon determining section, which, prior tocommencing reforestation, numerically expresses and defines presentconditions in the reforestation sites based on information that wascollected by the present condition information-collecting section 11. Inthe following explanation, amounts of accumulated carbon are determinedfrom a volume of the trees, and are used as an index for showingconditions in the reforestation sites. The method for calculating theamount of accumulated carbon will be explained later. Reference numeral13 represents a memory for storing an amount of accumulated carbon,which is determined by the amount of accumulated carbon determiningsection 12. Reference numeral 14 represents a planting tree-typedetermining section that determines the type of tree (tree-type) to beplanted in a reforestation site about to be reforested, based on theamount of accumulated carbon stored in the amount of accumulated carbonmemory 13. Reference numeral 15 represents a tree-type database, whichdefines beforehand information relating to tree-types and trees, and isconsulted by the planting tree-type determining section 14 whendetermining a tree-type. Reference numeral 16 represents a projectdevising section, which devises a project for reforestation by usingsimulation based on the tree-type determined by the planting tree-typedetermining section 14 and the amount of accumulated carbon stored inthe amount of accumulated carbon memory 13. Reference numeral 17represents a project database, which stores projects that were devisedin the project devising section 16.

Reference numeral 18 represents an indirect effect estimating section,which estimates possible indirect effects when reforestation is to beimplemented based on a project stored in the project database 17 andstores the estimation result in the project database 17. Referencenumeral 19 represents a risk estimating section, which estimatespossible risk when reforestation is to be implemented based on a projectstored in the project database 17 and stores the estimation result inthe project database 17. Reference numeral 20 represents a projectoutput section, which outputs projects, indirect effects, and risks,stored in the project database 17, through a display (not shown) and theinternet 4 to the reforestation site terminals 3. Reference numeral 21represents an indirect effect information collecting section, whichcollects information relating to indirect effects of forestation aroundreforestation sites, input from the reforestation site terminals 3.Reference numeral 22 represents a risk information collecting section,which collects information relating to risks of forestation, input fromthe reforestation site terminals 3. Reference numeral 23 represents aproject accomplishment status assessment section, which receivescondition information, indirect effect information, and riskinformation, respectively from the present conditioninformation-collecting section 11, the indirect effect informationcollecting section 21, and the risk information collecting section 22,and, based on this information, assesses the accomplishment status of aproject stored in the project database 17. Reference numeral 24represents a project review section, which reviews a project based onthe accomplishment status determination result in the projectaccomplishment status assessment section 23, and stores the reviewedproject in the project database 17.

Subsequently, an operation of devising and evaluating a reforestationproject will be explained with reference to FIGS. 1 and 2. Firstly, thereforestation implementer selects a plurality of proposed reforestationsites, and sets up reforestation local offices in the proposed sites. Atleast one reforestation site terminal 3 is installed in the localreforestation office. A present state information-collecting section 11instructs the reforestation site terminal 3 to input conditioninformation. Upon receiving the instruction, an operator in thereforestation site inputs forest investigation results from thereforestation site terminal 3. The above-described forest investigationresults mean to includes results that were obtained in local areas fromA1 to A7 in an proposed reforestation area A0, as shown in FIG. 3 byinvestigations relating to tree diameters at the breast height andheight of every tree in each of the local regions A1 to A7, and theforest investigation results contain information for identifying aproposed reforestation site and the local areas, and the tree diametersat the breast height and height of trees in each local region.

Next, the present condition information-collecting section 11 receivesthe forest investigation result information, and sends it to the amountof accumulated carbon determining section 12. Upon receiving theinformation, the amount of accumulated carbon determining section 12determines the amount of accumulated carbon by an estimation using thefollowing calculation equation (step S1).

The trunk volume V (m³) of each tree is calculated by V=dbh²×h×0.3.Here, dbh is the tree diameters at the breast height (m), and h is thetree height (m). Next, the trunk weight Wtdy (ton) of each tree iscalculated from the trunk volume V by Wt_(dry)=V×ρ₀. Here, ρ₀ is thespecific gravity of a tree in a state where it has been dried at a totaldry specific gravity temperature of 100 to 105° C. until its weightchange stops. Then, the trunk weight Wtdy that was determined ismultiplied by a carbon content rate of 0.5, and further multiplied by anenlargement coefficient of 1.6, to determine a total amount ofaccumulated carbon including branches, leaves, and roots. The amount ofcarbon thus obtained is the carbon amount for a tree. The amount ofaccumulated carbon is calculated for all the trees, and the amounts ofaccumulated carbon thus obtained are added together to obtain an amountof accumulated carbon for one local region. This calculation isperformed for all the local regions A1 to A7, and an average amount ofaccumulated carbon per unit area Ct (Cton/ha) is calculated. This valuecorresponds to an amount of accumulated carbon in the reforestation siteA0 (average amount of accumulated carbon per unit area). Since theamount of accumulated carbon obtained by the above process isproportional to the amount of carbon dioxide that is absorbed byexisting trees so far, the amount of accumulated carbon may be convertedto an amount of carbon dioxide absorbed so far by a unit area bymultiplying a predetermined coefficient to the amount of the accumulatedcarbon.

Next, the amount of accumulated carbon determining section 12 comparesthe amount of obtained accumulated carbon with a predeterminedthreshold, and classifies the reforestation candidate site into one ofthree types of reforestation sites (a) to (c), and, in accordance withthe classification result of the reforestation site, a site ofdeteriorated secondary forest where the amount of accumulated carbon iszero is selected as the reforestation site.

(a) Deteriorated Secondary Forest (Forest in a Bush State)

When the amount of obtained accumulated carbon 0.6 to 9.6 Cton/ha, thereforestation candidate site is classified as a deteriorated secondaryforest. Since this state cannot be expected to increase an amount ofaccumulated carbon, and this region is a region that need to be newlyforested.

(b) Secondary Forest with a Large Amount of Accumulated Carbon

When the amount of obtained accumulated carbon is greater than 9.6Cton/ha, this reforestation candidate site is classified as a secondaryforest with a large amount of accumulated carbon. Since a sufficientamount of accumulated carbon can be expected even at present, andtherefore, this forest must be preserved in its present condition, andthere is no room for reforestation project.

(c) Zero Accumulated Carbon Area

When the amount of obtained accumulated carbon is less than 0.6 Cton/ha,the reforestation candidate site is classified as site having zeroaccumulated carbon. This state means that this site must be newlyreforested.

Next, the amount of accumulated carbon determining section 12 stores theamount of accumulated carbon that was determined and the reforestationsite class obtained by the site classification process in the memory 13,and notifies the planting tree-type determining section 14 that theamount of accumulated carbon determining process has ended. Based on theamount of accumulated carbon and the reforestation site class determinedby the reforestation candidate sites classification process, sites whichare defined as the deteriorated secondary forest and are defined as thezero accumulated carbon area are determined as a reforestation sitewhere reforestation should be carried out.

Upon receiving the above notification, the planting tree-typedetermining section 14 reads the amount of accumulated carbon and thereforestation site class that is stored in the memory 13, and selectsand determines the type of tree to be planted in each reforestation site(step S2). The tree-type is determined by retrieving the tree-type datastored in the tree-type database 15. The tree-type data stored in thetree-type database 15 defines “standard amount of growth”, “harvestperiod”, “standard timber value”, “density when planting”, “density whenthinning”, “level of risk”, “soil suitable for planting”, “weathersuitable for planting”, and “average carbon amount”. The plantingtree-type determining section 14 retrieves the tree-type database 15,and selects and determines a tree-type that coincides with the requiredamount of accumulated carbon and the reforestation site class. Theplanting tree-type determining section 14 notifies the project devisingsection 16 of the tree-type that was selected and determined.

Subsequently, the project devising section 16 devises a project forreforestation (step S3). The project is devised based on foresting andharvest simulation results, shown below.

By carrying out simulations of harvest (main thinning) and reforestationafter planting a plurality of tree-types having different amount ofgrowth rates and harvest periods, the reforestation project which isoptimized for the reforestation purpose is determined by the followingsteps (1) to (10).

(1) First, growth rates for average tree height and average treediameters at the breast height are estimated based on measurement dataof existing forests, and a relationship between the age of a forest anddensity reduction of the number of standing trees is estimated and aplan for controlling density of trees in a site is established inaccordance with the age of the forest after tree planting. The growthrate is estimated based on an approximation of a growth curve.

When the number of tree-types is n, growth in the diameter (Di) andaverage height (Hi) for a tree-type, number i, can be approximated usingthe Mitcherlich equation, which is widely used as a growth curve, asfollows.Hi=mi·(1−L·hi exp (Ki·t))Di=Mi·(1−L·di exp (Ki·t))where mi, L·hi, ki, L·di, and ki are constants, and t is the age of theforest. It is possible to use existing data which are closest to thegrowth curve, and it is also possible to use conventional growth curves,known as Rodischick curve, Gonpeltz curve, or the like. However,constants of the growth curve are not limited to these, and it isacceptable to use any tables in which foregrade, average height, andaverage tree diameter at the breast height, are arrangedcorrespondingly.

Furthermore, it is known that density control of forests affects thegrowth rate of the tree diameter, and the diameter decreases when thedensity is high and increases when the density is low. However, undernormal forest management, it is possible to approximate the diametergrowth rate by the diameter growth curve described above. It isdesirable to obtain tables showing relationships between tree age anddensity for various tree-types.

(2) Next, relationships between the minimum tree diameter, standarddeviation of the tree diameter, and average diameter determined at agiven tree age, and the like, are determined, and a tree numberdistribution at each diameter grade is determined by using appropriatemodel equations representing the tree diameter distribution. In order todetermine the diameter distribution based on the average diameter, adistribution function must be determined. It is desirable to determine adistribution function which is close to the actual diameterdistribution. It is possible to adopt a distribution function whichfollows the normal distribution when trees are young, but the Weibulldistribution is often used for representing a diameter distribution oftrees in a normal forest.

When d represents a diameter at breast height, and x=d−a (a: constant,x>0), the Weibull distribution is expressed asf(x)=1−exp (−(x/b)^(c))(where b and c are constants).

Here, parameters a, b, and c are called a position parameter, a scaleparameter, and a shape parameter, respectively. As the positionparameter a, the minimum diameter is normally used. When it is assumedas distribution properties that the average value of distribution μ (notaverage diameter) of distribution is expressed by μ=D−a, and thedispersion is expressed by σ², μ and σ² can be represented by thefollowing equations.μ=bΛ(1+1/c) . . . (i)σ² =b ²{Λ(1+2/c)−Λ²(1+1/c)}. . . (ii)

In the above equations, since Λ(s) = ∫₀^(∞)x^(s − 1)𝕖^(−x)  𝕕x,D is the average diameter, and a, b, and c, are parameters. If values ofμ and σ² are obtained, the value c is determined for a certain value ofa by the following equation,${\sigma/\mu} = \frac{\sqrt{{\Lambda\left( {1 + {2/c}} \right)} - {\Lambda^{2}\left( {1 + {1/c}} \right)}}}{\Lambda\left( {1 + {1/c}} \right)}$and the value of b is determined from equation (i). That is, once theaverage value, the dispersion, and the value of a are known, the shapeof the distribution can be determined by calculating the values of b andc. A function expressed by Λ(s) = ∫₀^(∞)x^(s − 1)𝕖^(−x)  𝕕xis called a Λ(lamda) function, and, since it is difficult to solve theabove equation by mathematical analysis, the value is obtained by thefollowing approximate equation.Λ(s)=1−0.57710166(s−1)+0.98585399(s−1)²−0.87642182(s−1)³+0.8328212(s−1)⁴−0.5684729(s−1)⁵+0.25482049(s−1)⁶+0.0514993(s−1)⁷.

Some work is required to determine the parameters a, b, and c, whichdetermine the shape of the distribution. The average diameter D and theaverage tree height H at a tree age of t are known quantities, and thestandard deviation a and the minimum diameter a can be calculated basedon the average tree diameter D.

When the standard deviation a of the tree diameter is determined fromthe average tree diameter D, the standard deviation ca can be obtainedby regressive analysis from the average diameter, because it is knownthat there is a linear relationship between the average diameter and thestandard deviation for a plurality of artificial plantation. That is,the relationship between the standard deviation σ and the average treediameter D can be expressed by the approximation σ=m·D+n (where m and nare constants). Therefore, values for m and n can be determined frominvestigations regarding existing reforestation sites.

The standard deviation can be obtained not only by the primaryregression analysis as described above, but also it can be determinedfrom various relationships obtained by examinations of various sites.

In forests where the thinning have been implemented, since thesuppressed trees are removed, consequently the minimum diameter iscomparatively large; in forests, however, where thinning have not beenimplemented, many suppressed trees remain and the minimum diameter issmall. Although the minimum diameter may affect on the average diameterD, the shape of the tree size distribution, that is, the distributioncoefficient can be determined even when the average diameter D is set ata constant value.

Once the shape of the distribution has been determined, the area of onediameter grade ranging from a given diameter di to d+1 is obtained fromthe distribution coefficient, the number distribution of the diametergrade is determined. That is, the tree number distribution for eachdiameter grade per one ha is obtained by multiplying the number of treesper area (trees/ha) to determine the tree number distribution for eachdiameter grade per one ha.

(3) Subsequently, an appropriate equation indicating the relationshipbetween the tree diameter distribution and the tree heights for eachdiameter grade at a given tree age is determined. Generally, since thereis a correlation between the tree diameter and the tree height, it ispossible to estimate the tree height from the tree diameter by applyingan appropriate correlation equation, which is called a tree heightcurve. Moreover, it is known from experience that the tree height curve(including a linear relationship) bends at higher tree age region andbecomes less steep as the tree age increases. Although many types ofestimation equations have been elaborated, it is reasonable to expressthe tree height curve such an equation as 1/H=A+B/D. Here, H is the treeheight, D is the diameter, and A and B are constants. With regard to Aand B, it is necessary to carry out investigations of existing foreststo establish a method for determining these constants in advance fromthe average diameter (D) and the average tree height (H). Results ofinvestigations regarding many plots of Japanese pine, cedar, tropicalmelina, and the like, reveal that the relationship between H and A has afollowing relationship.A=a′+b′/H(where a′ and b′ are constants)

It is known that an estimated value of B can be obtained with highaccuracy from multiple regression analysis between A or B and theaverage tree height (H), and the value of B can be obtained by thefollowing equation.B=a″/D+b″/H+C″ (where a″, b″, and C″ are constants).Therefore, A and B can be estimated from the average tree height (H) andthe average diameter (D). It is possible, therefore, to obtain the treediameter distribution as well as the tree height distribution for agiven tree diameter.

(4) Subsequently, using a standard trunk shape, a top-diameter, timberlength, and the base-diameter can be calculated, assuming that cut treeshave been sawn into logs.

The standard trunk shape is determined for each tree-type in accordancewith the degree of tapering grade. However, since there is no bigdifference in the trunk shape for various tree types, one type of trunkshape can be selected as a standard size. It is convenient toapproximate the trunk shape by n-dimensional curve for expressing thestandard trunk shape, and a three-dimensional curve is normallysufficient to express the standard trunk shape. An example is shownbelow.

In order to standardize various tree shapes, the tree height is set 1when a tree height is 1.3 m, a tree diameter at the breast height is set1, and the top of the tree height is set as a point of origin (0,0), anthe tree height is represented along the x-axis in the direction fromthe top toward to the root, and the tree outside diameter is representedas y-axis in the radial direction, and the tree shape is approximated bya three-dimensional curve as y=ax+bx²+cx³, which passes the point oforigin (0,0) and the tree diameter at breast height (1,1).

That is, after harvest down a number of trees having different diametersand height, and tree height and tree diameters at the breast height aremeasured. The diameter at a given height is measured and the height xi,the diameter di, and D are plotted, yielding the following equations.xi=hi/(H−1.3)yi=di/Dwhere xi is the height at a position where the diameter was measured, diis the diameter at the height of hi, and D is the tree diameters at thebreast height.

A three-dimensional curve is approximated from these values by the leastsquare method. This three-dimensional curve represents the timbersurface including bark.

(5) Next, a tree diameter distribution is obtained based on therelationship between the standard deviation of the tree diameter of agiven tree age and the minimum tree diameter, and a tree height of agiven diameter grade is obtained based on the above-describedrelationships, the log volume is determined in the case of cuttingstanding trees in a diameter grade, and the log volumes for all diametergrades are determined and all of the log volumes for every log diametergrade is estimated from the whole forest.

Since the tree height Hi for a tree diameter at the breast height Di isdetermined, the diameter of the log obtained by the cutting andtimbering process can be determined from the standard trunk shape. Thatis, the standard trunk shape is multiplied by the tree height, and thediameter is multiplied by the tree diameters at the breast height, todetermine the tree shape of this tree, and the diameter at a givenheight is determined by calculation. When it is assumed that a tree iscut according to a conventional method, for instance, into a logs ofevery four meters from the root, the diameter and timber volume can becalculated and the timber volume for a diameter grade is obtained bymultiplying the number of trees per ha, and thereby a total volume ofevery tree diameter per area is obtained. At this time, since thediameter at a given height includes bark, the timber volume iscalculated by removing the bark thickness. This calculation process isrepeated from the minimum tree diameters at the breast height Dmin tothe maximum tree diameters at the breast height Dmax, and the totaltimber volume per ha is obtained. By further multiplying this by thearea, the total timber volume for each diameter for the whole forest canbe determined. When calculating the whole price, since the price oftendiffers according to the timber diameter, a timber volume and price arecalculated for each diameter grade, and the total sale price for all thetimber is calculated by adding every timber price for every diametergrade.

(6) Next, the economic value of the entire forest is determined bymultiplying the log volume by the log price of each diameter grade.

(7) Next, the timber volume prior to thinning and the timber volumeafter thinning are calculated assuming that the average diameter doesnot change, the relationship between the shape of diameter distribution,diameter, and tree heights, is maintained, and the number of trees onlychanges before and after thinning.

Thinning is often carried out while growing the forest. The aim ofthinning is to remove defective trees and hasten the growth of remainingtrees, while simultaneously earning some intermediate income. A growthrate of tree diameter is usually good after thinning, although theamount of growth differs according to the tree type, topography of theland, soil, amount of rainfall, and the tree density after thinning;since these factors are not generally elucidated, the effects aredetermined by experimental tests. For convenience, the calculation iscarried out assuming that trees with large and small diameters arethinned approximately evenly, or trees with large diameter side andtrees with small diameter sides of either side of the distribution arethinned preponderantly, and also assuming that the average diameter doesnot change after thinning, and only the standing tree density isreduced. The timber volume by thinning is assumed as that the timbervolume is caused by the difference of the number of trees afterthinning.

(8) Next, it is assumed that the timber volume obtained by thinning isthe tree volume corresponding to trees having the average diameter andthe average tree height of standing trees, and all timbers obtained bythinning are shipped. Main timbers are obtained by cutting standingtrees for thinning and all of the timber volumes is assumed to beshipped totally.

(9) Next, a growth simulation is carried out by repeating from thegrowth rate with age. This simulation is applied to a plurality oftree-types, and estimation is obtained for the growth of the forestvolume in terms of the timber volume and the price as the timber volumeof the reforestation site. Consequently, the average tree height,average diameter, distribution of diameter and tree heights, timbervolume, and sales price, can be obtained. Even when the tree-types aredifferent, the simulation can be equally calculated by the same equationby only changing the value of the equation depending on the tree-type.That is, a growth simulation for a reforestation site that includes aplurality of tree-types can be calculated by combining the amount of cuttimbers and the sales price for each tree-type.

(10) Finally, when a plurality of tree-types are grown in a regionhaving a certain area, for instance ten-thousand ha, by repeating thesequences of planting, thinning, harvest, and re-planting, it ispossible to select a combination of tree-types and the planting area, inorder to obtain the maximum profit after comparing various conditionssuch as tree-types, planting areas and the continuity of obtaining theprofit.

The planting and harvest plan can be established by linear programmingmethod that will maximizes the profit after the cost has been subtractedfrom sales. For example, a project can be established whereby ntree-types are planting in a site of no standing trees having areforestation target area of 10000 ha, with an operating period of sixtyyears, divided into twelve periods of five years, and, after the harvest(cutting all trees), one out of n types is selected and reforestation ofsuch a tree-type is carried out.

At this time, a combination is searched that maximizes the targetvariables by linear programming method.ΣΣΣ{Bi,k·Vi,k·Si,j,k+BTi,k·BRi,k·Xi,j,k−Pi,j·Si,j,k−Hi,j·Vi,j}where, Bi, k: timber price per m³ achieved by main-harvest tree-type iat an age grade k($/m³),

-   -   Vi, k: timber volume per ha achieved by main-harvest tree-type i        at an age grade k (m³/ha),    -   Si, j, k: harvest area of tree-type i at an age grade k in a        period j at set variables (ha)    -   BTi, k: timber price per m³ achieved by thinning tree-type i at        age k($/m³)    -   BRi, k: timber volume per ha achieved by thinning tree-type i at        age k (m³/ha)    -   Xi, j, k: harvest volume of tree-type i at age k in period j at        total variables (ha)    -   Pi, j: cost of reforestation of tree-type during period j at        total variables ($/ha)    -   Hi, j: cost of main harvest and transportation of tree-type i        during period j at total variables    -   BHi, j: cost of thinning, harvest, and transportation of        tree-type i during period j at total variables.

Moreover, a variety of limiting equations are generally attached to theabove. For example,

-   -   the entire 10000 ha are planted in the first period,    -   upper and lower limits are set for harvest volume, timber        volume, and sales price,    -   upper and lower limits are set forest standing tree timber        volume,    -   upper and lower limits are set reforestation volume of specific        tree-types,    -   amount of carbon dioxide absorbed (carbon fixed amount) is        determined from the timber volume and specific gravity, and        upper and lower limits are set,    -   and the like, numerical equations for various cases being        considered and used as restrictions when solving by linear        programming method.

When the profit is above a fixed value, priority is placed on factorsother than the profit. For example, a carbon fixed amount based onreforestation is provisionally calculated, and the priority is given onthe carbon fixed amount when profit is above the fixed value.Furthermore, when trading of carbon fixed amounts is possible, incomecorresponding to the carbon fixed amount should be added to the profit.Here, the carbon fixed amount is the increase in the carbon accumulationamount, with respect to the carbon accumulation amount that is used as areference value prior to reforestation, as the result of implementingreforestation in a predetermined period, and, in this predeterminedperiod, the carbon fixed amount is proportional to the carbon dioxidethat has been fixed due to the absorption by trees in a predeterminedperiod. The carbon fixed amount is calculated by subtracting the carbonaccumulation amount at the start of the calculating period from thecarbon accumulation amount at the end of the calculating period, or bydetermining the total absorption amount of CO₂ in each year within thetarget site.

By carrying out this simulation, the tree-type and planting area in eachreforestation site is determined, the tree-type and planting area ineach reforestation site is determined as the reforestation project, andthe project devising section 16 stores the devised project in theproject database 17. Furthermore, the reforestation devising period(normally thirty years) is divided by the project devising section 16(e.g. into thirty sections), and the growth change of trees in eachdivided period (one year) are calculated and stored in the projectdatabase 17. The amount of the growth change is stored as change in thecarbon accumulation amount, determined by the calculation to determinethe carbon accumulation amount described above.

Subsequently, after the project information has been stored in theproject database 17, the indirect effect estimating section 18 reads theproject information from the project database 17, and, effects on thesurrounding environment (step S4) is estimated in order to implementthis project. In particular, the negative influence in the surroundingenvironment in reforestation site is estimated, in contrast to thetarget to maximize the carbon fixed amount in the site. Types ofindirect influences are:

-   -   forest felling by burnt farming,    -   forest felling for consumption of timber as fuel wood,    -   forest felling for construction or other timber consumption, and    -   illegal trimming.

These indirect effects are estimated by storing estimated values basedon prior investigation of the scale of the reforestation and eachenvironment of the reforestation location, and reading the value thatcorresponds to the devised project.

Next, the indirect effect estimating section 18 stores the estimatedindirect effects in the project database 17.

Next, the indirect effect estimating section 18 reads the projectinformation from the project database 17, and, to implement thisproject, estimates the risk of danger (step S5). The types of risk are

-   -   insect damage,    -   forest fire, and    -   weather damage.

These risks are estimated by storing estimated values based on priorinvestigation of the scale of the reforestation and each environment ofthe reforestation site, and reading the value that corresponds to thedevised project.

Next, the indirect effect estimating section 18 stores the estimatedrisk in the project database 17.

Next, the project output section 20 reads the project information storedin the project database 17, and outputs it to the reforestation areaterminal 3 through output to a display (not shown) and the internet 4.

As a consequence, the project for reforestation is output, and thereforestation implementer implements reforestation based on this project(step S6).

At the time of implementing the project, when the indirect effects andrisks are extremely large, it is possible to re-examine and review theproject and to change the project to one having smaller indirect effectsand risks. In this way, by considering indirect effects and risks whendevising the project, it becomes possible to evaluate the projectaccurately.

Subsequently, an operation of reviewing a project based on results ofmonitoring present conditions during project execution will beexplained. Firstly, the reforestation implementer inputs present statessuch as the progress of the forest from the reforestation area terminal3, and transmits them to the reforestation project system 1. Thispresent condition information is received by the present conditioninformation-collecting section 11, which notifies the projectaccomplishment status assessment section 23. The reforestationimplementer inputs information relating to risks from the reforestationarea terminal 3, and transmits it to the reforestation project system 1.This risk information is received by the risk information collectingsection 22, which notifies the project accomplishment status assessmentsection 23.

Upon receiving this, the project accomplishment status assessmentsection 23 reads the project information from the project database 17,consults this project information and the information obtained from theinformation-collecting sections, and assesses the accomplishment statusof the project (step S7). The assessment of the accomplishment status ofthe project is executed by first determining the carbon accumulationamount in the sequence described above based on the present conditioninformation obtained from the present condition information-collectingsection 11, comparing the carbon accumulation amount that was determinedwith the carbon accumulation amount stored in the project database 17,and thereby calculating the accomplishment rate. Furthermore, indirecteffects and risk are calculated in the same manner from the state of thepresent condition of the project.

This determination result is output to the project review section 24,and also to a display (not shown) and a printer.

Next, the project review section 24 reviews the project if the projectprogram is not accomplished, based on the determination result of theaccomplishment status. Based on the determination result that wasnotified from the project accomplishment status assessment section 23,the project review section 24 outputs assumed reasons for thenon-accomplishment of the project stored beforehand to the display andthe printer. An operator receives those reasons, estimates the reasonswhy the project was not accomplished while estimating the reasons, andoutputs the estimated reasons through a keyboard (not shown) to theproject review section 24. Upon receiving the output, the project reviewsection 24 outputs a countermeasure, defined for each reason beforehand.The operator receives countermeasures and implements countermeasures(step S9). Then, the project review section 24 reviews the project byre-devising the project based on the project information stored in theproject database 17 (step S10).

Next, the project review section 24 newly stored the reviewed project inthe project database 17. Then, once the new project has been stored, theindirect effect estimating section 18 newly estimates indirect effectsby the operation described above, and stores them in the projectdatabase 17. Furthermore, the risk estimating section 19 18 newlyestimates risk by the above-described operation and stores them in theproject database 17.

The steps S7 to S10 shown in FIG. 2 are repeated at regular intervalsuntil the project period of the reforestation ends.

In this way, the reforestation project is devised based on the presentcondition of the reforestation site, while estimating indirect effectsand risks, thereby enabling the reforestation project to be devisedeasily. Further, while executing the project, the accomplishment statusof the project is assessed based on condition information, indirecteffect information, and risk information, and the project is reviewedbased on the assessments, which enables the reforestation projectreliably executed.

Although the preceding explanation describes the carbon accumulationamount and carbon fixed amount (increase in the carbon accumulationamount), it is possible to estimates the reforestation project by thecarbon dioxide absorption amount, and the carbon dioxide amount can beobtained by muliplying a predetermined coefficient to the carbonaccumulation amount or the carbon fixed amount. Since the carbon amountand the amount of carbon dioxide are proportionally related, the carbonamount may be substituted to the amount of carbon dioxide.

Further, a program for realizing the functions of all the processingsections in FIG. 1 may be stored in a computer-readable recordingmedium, and it is possible for the computer system to devise thereforestation project program by reading the program stored in therecording medium and by implementing the program. Here, the “computersystem” includes hardware such as OS and the surrounding equipment. Whena WWW system is being used, the “computer system” includes the websitesupply environment (or the display environment). Further,“computer-readable recording medium” refers to portable media such as aflexible disk, an optical magnetic disk, an ROM, a CD-ROM, and to memorydevices such as a hard disk in the computer system. Moreover,“computer-readable recording medium” includes media that store a programfor a fixed period of time, such as a volatile memory RAM inside acomputer system comprising a server and clients in the case where theprogram has been transmitted through a network, such as the internet, ora communications line, such as a telephone line.

Further, the abovementioned program may be transmitted from the computersystem that stored the program in the memory device or the like toanother computer system through a transmitting medium, or bytransmission waves in a transmitting medium. Here, the “transmittingmedium” that transmits the program refers to a medium having a functionfor transmitting information, such as a network (communication net) suchas the internet, and a communication line system (communication line)such as a telephone line system. Moreover, these functions can berealized in combination with programs already stored in the computersystem, achieving a differential file (differential program).

A preferred embodiment of the invention has been described above withreference to the drawings, but the specific constitution is not limitedto this embodiment, and the design may be modified in various wayswithout departing from the scope of the present invention.

Industrial Applicability

This invention relates to a reforestation project system and areforestation project program that can devise and evaluate areforestation project in order to reduce a greenhouse effect gasdischarge. Thus, the reforestation project system is useful in selectinga site for reducing the carbon dioxide discharge by providing a computerserver capable of communicating with terminals installed in sites, aproject database for storing reforestation projects, a tree-typedatabase, a condition information-collecting means for collecting thetree diameters at the breast height and tree heights of trees withinlocal regions. This invention is applicable to reforestation project toan area where carbon dioxide discharge is desired by selecting a regionwhich is most effective for reducing carbon dioxide in the area.

1. A reforestation project system comprising: a computer server capable of communicating through the internet with terminals installed in sites where reforestation is carried out, for devising and evaluating a reforestation project; a project database for storing reforestation projects; a tree-type database, in which tree-type data for each tree-type are stored; a condition information-collecting means for collecting the tree diameters at the breast-height and tree heights within local regions in a plurality of proposed reforestation sites input from said terminals; a reforestation site determining means for determining a reforestation site by calculating carbon dioxide absorption amounts by a predetermined equations at each proposed reforestation sites from the tree diameters at the breast-height and tree heights in said local regions, and selecting a reforestation site having a determined carbon dioxide absorption amount that is smaller than a first threshold; a project planning means for calculating a profit when planting area in said reforestation site and the tree-types stored in said tree-type database are respectively changed, selecting a tree-type and the planting area that can obtain the greatest profit, and storing the selected tree-type, planting area, and estimated values for growth change of the trees, as reforestation project information in said project database; and a project output means for displaying said reforestation project information, stored in said project database, at said terminals.
 2. A reforestation project system comprising: a computer server capable of communicating through the internet with terminals installed in sites where reforestation is carried out, and devising and evaluating a reforestation project; a project database for storing obtained reforestation projects; a tree-type database, in which tree-type data for each tree-type are stored; a condition information-collecting means for collecting the tree diameters at the breast height and tree heights of all trees within each local region in a plurality of reforestation candidate sites input from said terminals; a reforestation site determining means for performing a predetermined calculation to determine the average carbon dioxide absorption amount per unit volume at the present point in the reforestation candidate site, from the tree diameters at the breast height and tree heights that were received, selecting a reforestation candidate site having a determined average carbon dioxide absorption amount that is smaller than a first threshold, deeming this reforestation candidate site to be the reforestation site, and outputting the tree diameters at the breast height and tree heights of the trees in the reforestation candidate site, and information for identifying the reforestation candidate site; a first calculating process that inputs said tree diameters at the breast height and tree heights, and calculates the average diameter and average tree height at each tree age; a second calculating process that determines tree number distribution and tree height distribution for each tree diameter by calculation; a third calculating process that determines log volume of each diameter per unit area, based on said tree number distribution and tree height distribution for each tree diameter, by calculation; a fourth calculating process that multiplies the reforestation site area by said log volume, thereby determining the log volume of the entire reforestation site, and multiplies this log volume of the entire reforestation site by a log price for each diameter, thereby determining a economic value for the entire reforestation site; a project devising means for repeatedly executing the first, second, third, and fourth calculating process for each tree-type stored in said tree-type database so as to determine the economic value of the entire reforestation site in the case where the reforestation site volume has been changed, selecting a tree-type and reforestation site volume that obtain the highest economic value determined by said fourth calculating process, and storing the selected tree-type, planting area, and estimated values for growth change of the trees, as reforestation project information in said project database; and a project output means for displaying said reforestation project information, stored in said project database, at said terminals.
 3. The reforestation project system according to claim 1, further comprising an indirect effect memory means, in which is stored beforehand information relating to indirect effects of each environment of the reforestation site and the scale of the reforestation, obtained by prior investigation; a risk memory means, in which is stored beforehand risk information of each environment of the reforestation site and the scale of the reforestation, obtained by prior investigation; an indirect effect estimating means, which reads a project value of indirect effects corresponding to the scale of the reforestation project and the reforestation site, read from said project database, from said indirect effect memory means, and stores it in said project database; and a risk estimating means, which reads a project value of risks corresponding to the scale of the reforestation project and the reforestation site, read from said project database, from said risk memory means, and stores it in said project database.
 4. The reforestation project system according to claim 3, further comprising an indirect effect collecting means, which receives and collects condition information relating to indirect effect estimates, input from said terminal; a risk collecting means, which receives and collects condition information relating to risk estimates, input from said terminal; a project accomplishment status determining means, which receives condition information, indirect effect information, and risk information, respectively from the condition information-collecting means, the indirect effect information collecting means, and the risk information collecting means, compares them with estimate values and project values that are stored in said project database, and calculates a proportion of conditions with respect to said project; and a project review means, which, when said reforestation project is deemed incomplete from the proportion of conditions with respect to said project, re-devises said reforestation project, and stores it in said project database; said indirect effect estimating means and risk estimating means re-estimating indirect effect and risk based on the reviewed project that was stored in said project database.
 5. The reforestation project system according to claim 1, wherein a second threshold smaller than said first threshold is set, and, in the case where the amount of carbon dioxide obtained is smaller than said first threshold and greater than said second threshold, the present secondary forest is cut and deemed a reforestation site for new reforestation.
 6. A reforestation project program, operated on a reforestation project system that comprises a computer server capable of communicating through the internet with terminals installed in sites where reforestation is carried out, and devising and evaluating a reforestation project, the computer server being comprised of a project database for storing reforestation projects and a tree-type database, which tree-type data for each tree-type are stored in, the reforestation project system allowing a computer to execute a condition information-collecting process for collecting tree diameters at the breast height and tree heights within local regions in a plurality of reforestation candidate sites input from said terminals; a reforestation site determining process of determining a reforestation site by performing a predetermined calculation to determine carbon dioxide absorption amounts at the present point in the reforestation candidate sites from the tree diameters at the breast height and tree heights of trees in said local regions, and selecting a reforestation candidate site having a determined carbon dioxide absorption amount that is smaller than a first threshold; a project devising process of performing a predetermined calculation to determine profit when planting area in said reforestation site and the tree-types stored in said tree-type database are respectively changed, selecting a tree-type and planting area that can obtain the greatest profit, and storing the selected tree-type, planting area, and estimated values for growth change of the trees, as reforestation project information in said project database; and a project output process of displaying said reforestation project information, stored in said project database, at said terminals.
 7. A reforestation project program, operated by a reforestation project system that comprises a computer server capable of communicating through the internet with terminals installed in sites where reforestation is carried out, and devising and evaluating a reforestation project, the computer server being comprised of a project database for storing reforestation projects and a tree-type database, which tree-type data for each tree-type are stored in, the reforestation project system allowing a computer to execute a condition information-collecting process of collecting the tree diameters at the breast height and tree heights of all trees within each local region in a plurality of reforestation candidate sites input from said terminals; a reforestation site determining process of performing a predetermined calculation to determine the average carbon dioxide absorption amount per unit volume at the present point in the reforestation candidate site, from the tree diameters at the breast height and tree heights of all trees that were received, selecting a reforestation candidate site having a determined average carbon dioxide absorption amount that is smaller than a first threshold, deeming this reforestation candidate site to be the reforestation site, and outputting the tree diameters at the breast height and heights of all trees in the reforestation candidate site, and information for identifying the reforestation candidate site; a first calculating process of inputting said tree diameters at the breast height and tree heights, and calculating the average diameter and average tree height at each tree age; a second calculating process of determining tree number distribution and tree height distribution by inputting tree diameters at the breast height and tree heights by calculation; a third calculating process of determining a log volume of each diameter per unit area, based on said tree number distribution and tree height distribution for each tree diameter by calculation; a fourth calculating process of multiplying the reforestation site area by said log volume, thereby determining the log volume of the entire reforestation site, and multiplying this log volume of the entire reforestation site by a log price for each diameter, thereby determining a economic value for the entire reforestation site; a project devising process of repeatedly executing the first, second, third, and fourth calculating process for each tree-type stored in said tree-type database so as to determine the economic value of the entire reforestation site in the case where the reforestation site volume has been changed, selecting a tree-type and reforestation site volume that obtain the highest economic value determined by said fourth calculating process, and storing the selected tree-type, planting area, and estimated values for growth change of the trees, as reforestation project information in said project database; and a project output process of displaying said reforestation project information, stored in said project database, at said terminals.
 8. The reforestation project program according to claim 7, further allowing a computer to execute an indirect effect memory process of storing beforehand information relating to indirect effects of each environment of the reforestation site and the scale of the reforestation, obtained by prior investigation; a risk memory process of storing beforehand risk information of each environment of the reforestation site and the scale of the reforestation, obtained by prior investigation; an indirect effect estimating process of reading a project value of indirect effects corresponding to the scale of the reforestation project and the reforestation site, read from said project database, from said indirect effect memory means, and storing it in said project database; and a risk estimating process of reading a project value of risks corresponding to the scale of the reforestation project and the reforestation site, read from said project database, from said risk memory means, and storing it in said project database.
 9. The reforestation project program according to claim 8, further allowing a computer to execute an indirect effect collecting process of receiving and collecting condition information relating to indirect effect estimates, input from said terminal; a risk collecting process of receiving and collecting condition information relating to risk estimates, input from said terminal; a project accomplishment status determining process of receiving condition information, indirect effect information, and risk information, respectively in the condition information-collecting process, the indirect effect information collecting process, and the risk information collecting process, comparing them with estimate values and project values that are stored in said project database, and calculating a proportion of conditions with respect to said project; and a project review process of re-devising said reforestation project and storing it in said project database when said reforestation project is deemed incomplete from the proportion of conditions with respect to said project,; said indirect effect estimating process and risk estimating process re-estimating indirect effect and risk based on the reviewed project that was stored in said project database.
 10. The reforestation project program according to claim 6, wherein a second threshold smaller than said first threshold is set, and, in the case where the amount of carbon dioxide obtained is smaller than said first threshold and greater than said second threshold, the present secondary forest is cut and deemed a reforestation site for new reforestation. 